During the First World War, he served as director of a sanitorium in Belgium. In 1919 he became a professor of Psychiatry and Neuropathology at Jena. In 1920 he became Chief Doctor and scientific leader at Dr. Heinrich Lahmann's sanatorium Weisser Hirsch in Dresden. In 1924, he established himself as a psychiatrist in Berlin.

From 1933 Schultz wrote a relationship guidebook.[2] - with very liberal views. There he propagated the "extermination" of handicapped people ("Action T4")[3] and persecution of homosexual men was part of his activity at the Göring Institute. Schultz believed that homosexuality was hereditary and curable. On the one hand the institute tried to cure homosexuals,[4] while on the other Schultz led a commission that compelled those suspected of homosexuality to have intercourse with female prostitutes. The "guilty" were transported to concentration camps.[5]

In 1956, he became editor of the journal Psychotherapie, and in 1959 founder of the German Society for Medical Hypnosis (Deutschen Gesellschaft für ärztliche Hypnose).

His most famous achievement was the development of autogenic training, that was based on the hypnosis research and self-experimentation. It was first publicly put forward in 1926 as "autogenic organ exercises," and received its current name in 1928. The program uses daily practice sessions of visualizations that are designed to help the practitioner achieve deep relaxation.